# Posts by Jen

Total # Posts: 3,505

**history**

Muslims gained military ideas during the Crusades. How was this a positive effect?

*March 17, 2013*

**Chemistry**

ou are given the following data. S(s) + 3/2 O2(g) → SO3(g) ΔH = -395.2 kJ 2 SO2(g) + O2(g) → 2 SO3(g) ΔH = -198.2 kJ Calculate ΔH for the reaction below. S(s) + O2(g) → SO2(g)

*March 13, 2013*

**Biochemistry**

Explain how to prepare 1L of a buffer at pH 7.4 using 1M hypochlorous acid (Ka = 3.5 x 10-8) and a 1 M NaOH solution. Indicate the volume of hypochlorous acid and sodium hydroxide to use.

*March 13, 2013*

**Biochemistry**

Explain how to prepare 1L of a buffer at pH 7.4 using 1M hypochlorous acid (Ka = 3.5 x 10-8) and a 1 M NaOH solution. Indicate the volume of hypochlorous acid and sodium hydroxide to use.

*March 12, 2013*

**finance**

Assume investors expect a 2.0 percent real rate of return over the next year. If inflation is expected to be 0.5 percent, what is the expected nominal interest rate for a one-year U.S. Treasury security?

*February 17, 2013*

**chemistry**

Please help me with this dilution. Given a very concentrated tube of virus. Apply serial dilution to make 1:7500 dilution. Dilute virus in PBS

*February 16, 2013*

**math**

What is the height of a cliff if at 10 am the shadow is 2 feet long?

*February 6, 2013*

**math**

Find a subset of R^2 which is not of the form AxB where A and B are subsets of R.

*January 28, 2013*

**biochem**

Which of the following pairs of compounds would NOT make a hydrogen bond with each other? CH3 and H20 H20 and HF NH4 and HF H2O and CH3COOH all of the following would make hydrogen bonds

*January 27, 2013*

**math**

To find 6x8 i can use the facts for 5x4 and 1x4. do you agree, if so explain

*January 25, 2013*

**probability**

for a small regional airline, the number of claims for missing luggage averages 70 per week. a. what is the probability that on a given day, there are fewer than 3 claims made against the airline? b. what is the probability that there are more than 3 claims against the ...

*January 22, 2013*

**math**

• regular rate: $2.10/lb • ship 101 to 500 lb, get a 20% discount • ship over 500 lb, get a 40% discount A large medical supply company has promised to donate 12 hospital beds and 4 wheeled stretchers over four months. Each bed weighs 58 kg and each stretcher ...

*January 16, 2013*

**math.**

A band poster that measures 90 cm by 40 cm is reduced by a scale factor of 1/6 so it can fit on a postcard. a) What are the dimensions of the postcard image? b) By what scale factor, to the nearest hundredth, was the area of the poster decreased in the reduction process? ...

*January 15, 2013*

**math**

bob can fill bucket in 25 seconds in the sink, sue can fill same bucket in 17 seconds with hose, how much longer will it take bob to fill 15 buckets

*January 15, 2013*

**Math**

Given the following question: -3e^(-2*t)*sin(pi*t + pi/3)] How do I find a) period b) frequency c) time (phase) shift d) time constant

*January 12, 2013*

**Math**

ABC Bank offers a savings account with 4.5% compounded quarterly. Find the APY the bank's savings account offers (round your answer to three decimal places).

*January 9, 2013*

**maths-calculus**

mean value theorem prove sq root 9.1 is less than or equal to 3+1/60

*January 1, 2013*

**chemistry**

How many different 5.00 d states does hydrogen have? please list them..

*December 15, 2012*

**Intermediate college algebra**

Beer cans are right circular cylinders. My algebraic ale and logarithmic lager cans, from snide brewery, have dimensional units called brewskis. The have a volume (in cubic brewskis) equal to the solution of the number of grams of radium 226 remaining after 4860 years when the...

*December 13, 2012*

**CHE MISTRY**

149ml bubble of hot gases at 217 degrees celcius and 1.78 atm escapes from an active volcano. What is the temperature, in celcuis, of the gas in the bubble outside the volcano if the new volume of the bubble is 164ml and the pressure is 0.770atm?

*December 13, 2012*

**Intermediate college algebra**

Beer cans are right circular cylinders. My algebraic ale and logarithmic lager cans, from snide brewery, have dimensional units called brewskis. The have a volume (in cubic brewskis) equal to the solution of the number of grams of radium 226 remaining after 4860 years when the...

*December 12, 2012*

**8th Grade Math**

27,600 miles

*December 7, 2012*

**Chemistry**

How many kilograms of chalcopyrite must be mined to obtain 315g of pure Cu?

*November 28, 2012*

**Chemistry**

Calculate the pH of 30.0 mL of 0.025 M NaOH

*November 27, 2012*

**Chemistry**

Calculate the pH of 30.0 mL of 0.025 M NaOH

*November 27, 2012*

**chemistry**

the gas contained in a piston is compressed from an original volume of 1.15 L to a new volume of 0.45 L. Assuming that the temperature of the gas remains constant what is the new pressure exerted on the gas if the original pressure was 2.15 atm?

*November 26, 2012*

**chemistry**

the gas contained in a piston is compressed from an original volume of 1.15 L to a new volume of 0.45 L. Assuming that the temperature of the gas remains constant what is the new pressure exerted on the gas if the original pressure was 2.15 atm?

*November 26, 2012*

**chemistry**

How would you prepare a supersaturated solution of CuSo4 in 100ml of water

*November 24, 2012*

**physics**

Don't over-complicate it! If the 100 coil spring is capable of stretching 0.210 m, then a spring of half this length would be able to stretch 0.210/2 or 0.105 m. Literally no equations are even required!

*November 17, 2012*

**physics**

Your physics teacher drives an ideal frictionless car of mass 1000 kg which coasts along the level road to his home at a constant speed of 48 km/h with the engine turned off. It then coasts 40 m up his sloping driveway and comes to rest at the top without any braking required...

*November 3, 2012*

**chemistry**

If 75mL of a hard water sample required 23.00 mL of .200 M EDTA, calculate the total hardness

*November 1, 2012*

**chemistry**

MX2(s)<--> M2+(aq)+ 2X-(aq) ksp=[M2+][X-]2 the question asks.. why is [MX2] not used in the expression for the equilibrium? is it because they aren't used in the expressions?

*October 29, 2012*

**chem**

Use the solubility rules. If a compound is aqueous it splits into its ions, while if it is a solid (like FeO) or a liquid (like H2O) they ions do not separate. Hope this helps!

*October 29, 2012*

**math**

Assume that the average annual salary for a worker in the United States is $30,500 and that the annual salaries for Americans are normally distributed with a standard deviation equal to $6,250. Find the following: (A) What percentage of Americans earn below $19,000? (B) What ...

*October 25, 2012*

**chemistry**

One buffer solution used to calibrate a pH electrode was made by dissolving 2.24g of potassium propanoate, C2H5COOK, in 250cm3 of 0.20 mooll-1 propanoic acid.

*October 24, 2012*

**Science**

How can community growth affect local ecosystems?

*October 13, 2012*

**Analyzing Data (HELP!!)**

Multiplying Rabbits Suppose that a pair of rabbits produces six offsrping: 3 males and 3 females. Assumes that no offspring die. 1. If each pair of rabbits breeds only once, how many offspring would be produced each year for 5 generations? 2. Construct a graph of your data. ...

*October 8, 2012*

**physics**

A car accelerates uniformly from rest to a speed of 21.2 km/h in 8.3 s. Find the distance it travels during this time. Answer in units of m

*September 26, 2012*

**Physics**

A certain freely falling object requires 1.50 seconds to travel the las 30.0 meters before it hits th ground. From what height above the ground did it fall?

*September 22, 2012*

**geometry**

Supplementary means they equal to 180. Based on this, if one is acute (50) then the other would have to add up to equal 180 (so, 130). Why is this false? Because it could also be 90 degree angles -- 90 + 90 = 180 In this case, neither is acute!

*September 18, 2012*

**math**

On our worksheet this is the same question, but ours states the original ratio of red to yellow as 3:4.

*September 9, 2012*

**social studies**

word that means the division of land

*September 5, 2012*

**science**

Express 2.5 km in m____________, 4.7 m in mm ____________, and 14 cm in μm

*August 27, 2012*

**science**

Suppose your room had been 20 meters wide. Express this width in μm

*August 27, 2012*

**Chemistry IR Spectroscopy**

It's correct! Thanks

*August 25, 2012*

**Chemistry IR Spectroscopy**

Sort the compounds: conjugated or non conjugated. -but-2-enoic acid -butanoic acid -hex-4-en-3-one -hexan-3-one

*August 25, 2012*

**Chemistry**

Thanks!

*August 25, 2012*

**Chemistry**

Suppose you have a strong peak at 2230 cm–1. What is the wavelength of the radiation that was absorbed?

*August 25, 2012*

**math**

Using the distributive property of multiplication over addition, we can factor as in x2 + xy = x1x + y2. Use the distributive property and other multiplication properties to factor each of the following: 47.99 + 47 (x+1)Y +(X+1) x^2y+z^x3

*August 21, 2012*

**ma**

Simplify each of the following using properties of exponents. Leave answers as powers a.3^8.3^4 b.5^2.5^4.5^2 c.6^2.2^2.3^2

*August 21, 2012*

**Chemistry**

Assume your sample spots are 1 cm above the bottom of the TLC plate. What happens if you put the plate in a developing chamber that has 1.2 cm of developing solvent? A. The solvent will move up the plate by capillary action faster. B. The sample spots will become more ...

*August 18, 2012*

**Chemistry**

Why do you spot multiple times? Select one or more correct answers. A. To fill the capillary almost instantly by capillary action. B. So the developing chamber solvent does not evaporate. C. The higher compound concentration facilitates visualization. D. To acheive a high ...

*August 18, 2012*

**OCHEM DR BOB PLEASE HELP!!!!!!!!!1**

Why is it possible to use melting point to distinguish the different stereochemistry of the products? (Hint: what is the relationship of the different stereoisomers of the product?)

*August 15, 2012*

**chemistry**

Why is it possible to use melting point to distinguish the different stereochemistry of the products? (Hint: what is the relationship of the different stereoisomers of the product?)

*August 15, 2012*

**Chemistry**

Assume the solubility of benzoic acid in ice-cold water is 1.70 g/L and the solubility of benzoic acid in hot water is 68.0 g/L. Calculate the minimum volume of water (in mL) needed to recrystallize 0.950 g of benzoic acid.

*August 12, 2012*

**CHEMistry**

A mixture of two compounds, A and B, was separated by extraction. After the compounds were dried, their masses were found to be: 117 mg of compound A and 91 mg of compound B. Both compounds were recrystallized and weighed again. After recrystallization, the mass of compound A ...

*August 12, 2012*

**OCHEM**

A student needed to determine the percent composition of a mixture that contained fluorene and benzoic acid. The student took 245 mg of the mixture and used the extraction method to separate the components. Then both compounds were recrystallized and dried. The experiment ...

*August 12, 2012*

**HEALTH**

It is C because there are various causes for depression. Depression tends to depend on the person and their situations, but then it can also depend on their genetics. Considering there are so many large ranges and since depression itself is such a broad term, there is not a ...

*August 11, 2012*

**chem**

Of 1.00g of A reacts with 1.50g of B, what is the mass of C how do i do this? Law of conservationn of mass, but not sure where to start?

*July 26, 2012*

**Literacy**

B Historical data or the source of the quote, is the correct answer. Just took the test, on page 43.

*July 22, 2012*

**Chem Two**

When 2.25 g of a nonelectrolyte solute is dissolved in 125 mL of water at 22 °C, the resulting solution exerts an osmotic pressure of 955 torr. What is the molar concentration of the solution? How many moles of solute are in the solution? What is the molar mass of the solute?

*July 14, 2012*

**chemistry**

OH I THINK I MADE A MISTAKE. I GOT 55.7 AS MY ANSWER NOW

*July 12, 2012*

**chemistry**

A 100.0 ml sample of 0.300 M NaOH is mixed with a 100.0 ml sample of 0.300 M HNO3 in a coffee cup calorimeter. Both solutions were initially at 35.0 degrees celcius; the temperature of the resulting solution was recorded at 37.0 degrees celcius. Determine the delta H (in units...

*July 12, 2012*

**history**

Which country lawyer from Ashtabula, Ohio, argued that criminals are not born, but are made by the unjust condition of human life?

*July 9, 2012*

**stastics**

If 1.5% of the bolts made by an automotive factory are defective, what is the probability that in a shipment of 200 bolts, there are 6 defective bolts? Place your answer, rounded to four decimal places, in the blank.

*July 8, 2012*

**Chemistry**

I was just having trouble with getting the [OH-] concentration. I had the answer just didn't know how to get to it. Thank you, it helped.

*July 8, 2012*

**Chemistry**

This question was posted: At 22 °C an excess amount of a generic metal hydroxide M(OH)2, is mixed with pure water. The resulting equilibrium solution has a pH of 10.56. What is the Ksp of the compound at 22 °C? I have found my [OH-] concentration (3.63x10^-4) but I am ...

*July 8, 2012*

**math**

Given a dilation with the origin O (0, 0), by observation determine the scale factor "k." DO,K = (6, 12) (3, 6) What is the scale factor K = a0 Is the dilation an expansion or contraction? a1

*June 28, 2012*

**Beginner Alegra**

That was sooo much easier than I was making it out to be. Thank you!

*June 17, 2012*

**College Algebra**

Algebra! Not Alegra.

*June 17, 2012*

**Beginner Alegra**

From a point on a straight road, Nico and Maria are riding bicycles in the same direction. Nico rides at 12mph and Maria rides at 14mph. In how many hours will they be 11 mi apart?

*June 17, 2012*

**Physics**

A block of mass 77.0kg is placed at the top of a frictionless plane that is inclined 46 degrees to the horizontal. The height of the plane is 23.0 meters. Find the speed of the block at the bottom of the plane. Please show all your steps, don't just suggest a formula. ...

*June 11, 2012*

**Physics**

Fabulous! Thank you!!!

*June 11, 2012*

**Physics**

Question though, the answer in the book says that the answer is 3.9 Newtons...do I need to convert this answer or something?

*June 11, 2012*

**Physics**

Find the magnitude of the gravitational attraction force that the earth exerts on a 62-kilogram astronaut who is 8.00 X 10^7 meters away from the center of the earth. Useful numbers: M^earth=5.98 X 10^24kg; G=6.67 X 10^-11 N*m^2kg^-2 Please walk me through your steps, don'...

*June 11, 2012*

**Physics**

The liquid in the tube has a density of 1.48 g/cm^3 . The atmospheric pressure is 1.013 X 10^5 newtons per square meter. What is the pressure P in the container? Please walk me through your steps, don't just suggest a formula. Thank you very much.

*June 11, 2012*

**Physics**

I know it IS really fast lol, but that's what is says! Thank you for your help!

*June 11, 2012*

**Physics**

A wheel is rolling ithout slipping at 487 meters per second to the right on a level surface. the diameter of the wheel is 100 centimeters. What is the angular speed of the wheel in revolutions per minute? Please walk me through your steps, don't just suggest a formula. ...

*June 11, 2012*

**Physics**

Thank you so much!!

*June 11, 2012*

**Physics**

A particle moved along the x axis with a constant acceleration of -85.0 meters per second squared. The initial position of the particle was at the origin and its initial velocity was +325 meters per second. Find the position of the particle at T=4.0 seconds. Please walk ...

*June 11, 2012*

**Physics**

Oh my goodness, thank you so much! I was trying to do so much more then I needed too!

*June 11, 2012*

**Physics**

A car slowed down at a constant rate from 32meters per second to 3.0 meters per second in 9.0 seconds. What was the distance the car traveled in 9.00 seconds? Please show all steps, thank you very much.

*June 11, 2012*

**chemistry**

When you add 100ml of a 0.1M HCl solution to 200 ml of 0.4M NaOH solution what is the pH? can you please show detailed work. o don't understand this

*June 8, 2012*

**algebra**

if a wall is 34 feet, how tall must a ladder be to reach the top if at a 75 degree angle

*June 5, 2012*

**chemistry**

if 7.50g of Na2CO3 reacts, how many moles of CO2 are produced?

*May 28, 2012*

**algebra**

if lisa studies for 9 hours and gets a score of 75. How long would she have to study to get a score of 94

*May 26, 2012*

**physics..**

what's the density of a box whose weight is 1648 newtons and whose volume is 2.8 cubic meters? Will it float in a liquid whose density is 600 kilograms per cubic meter?

*May 24, 2012*

**physics**

if the pulleys are massless and frictionless and the rope is of negligible mass, and aristotle wanted to raise the 332 newton weight to a height of 6 meters. A-find the magnitude of force F he needed to pull on the rope to move the weight upward with a constant velocity. B-...

*May 24, 2012*

**physics**

the supports are on each end and the weight is in the middle

*May 24, 2012*

**physics**

A weightless beam rests on two supports. The beam supports a weight of 120 newtons. What are the magnitudes of the forces on each end ( A & B) of the beam?

*May 24, 2012*

**physics**

again-set up?

*May 24, 2012*

**physics**

A female whose mass is 130 kilograms is standing on a scale in an elevator that has an initial downward velocity of 6 meters per second and is accelerating upward at 7 meters per second. What's the magnitude of the apparent weight indicated by the scale?

*May 24, 2012*

**physics**

I'm confused as how you'd set these up..

*May 24, 2012*

**physics**

Trenton struggled as he lifted a 27kg mass vertically a distance of 9 meters in 4minutes with a constant velocity. A-how much work did he do? B-What was the average power comsumption in watts?

*May 24, 2012*

**physics**

Forces of 1,5,3, and F newtons are applied to a weightless board that rests on a fulcrum. The board doesn't rotate-what's the magnitude of the force F?

*May 24, 2012*

**physics**

a 1462 kilogram block was lifeted vertically at a constant velocity a distance of 0.08 x 10(to the 6th power) meters in 5minutes. A-how much work was done? B-what was the average power consumption in watts?

*May 24, 2012*

**physics**

not helpful..

*May 24, 2012*

**physics**

Three forces are applied to a box wrench. find the total torque about the bolt in newton-meters caused by these forces. Is the torque a positive torque or a negative torque?

*May 24, 2012*

**physics**

wonderful, ty

*May 24, 2012*

**physics**

The density of an unspecified material is 3.27 g/cm (cubed) . if the mass of a block of this material is 10.9kg, what is the volume of the block in cubic meters? A Wooden block is pulled to the right across a level surface at a constant velocity by a force of 47 Newtons, the ...

*May 24, 2012*